This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have begun to examine both receptors and signaling molecules displayed on beads for flow cytometry (Nolan and Sklar, 1998;Sklar et al. 2000). We have shown conditions under which his-tagged receptors may be bound to Ni2+ beads and bind ligand. We have also shown that solublized receptors may be reconstituted with heterotrimeric G proteins (subunits from Neubig) and arrestins (Prossnitz) for fluorescence, and potentially for flow cytometric analysis. We have attempted to use arrestin, receptors, as well as biotinylated receptor tail peptides as bait on beads. We are examining biotinylated anti-his antibodies instead of chelated Ni2+ beads.